A variety of different type of hose coupling devices are generally known. For example, U.S. Pat. No. 4,266,813 to Oliver and U.S. Pat. No. 4,586,733 to Andersen, Jr. disclose universal couplers which are used for attaching to hoses or bottles with different thread diameters and thread pitches; with Andersen, Jr. being used primarily for chromatography equipment. U.S. Pat. No. 4,126,338 to Cole et al. discloses a threaded coupling in which the connecting threads are disposed on a replaceable sleeve; and U.S. Pat. No. 4,236.736 to Andersen discloses hose coupling having means for gripping the ends of the hoses to be connected.
Moreover, U.S. Pat. No. 3,243,209 to Chertok discloses a high pressure fitting used in union connections, and U.S. Pat. No. 786,516 to phelan discloses a substitute for union-type connectors.
Pipe connectors having left-hand and right-hand threads are also known. For example, U.S. Pat. No. 3,381,978 to Faustini and U.S. Pat. No. 176,796 to Martin each disclose connectors having such oppositely threaded sections. U.S. Pat. No. 470,238 to Goodman also discloses oppositely threaded sections, but relates to a safety bolt.
Additionally, U.S. Pat. No. 2,443,394 to Le Clair discloses a union-type coupling device. The Le Clair device includes a ferrule having a shoulder and a cylindrical portion. An inner part of a union nut is slid over the cylindrical portion of the ferrule and is slidably and turnably lodged between the shoulder and the collar fitted at the end of the cylindrical portion. Means are provided for preventing unscrewing of the outer part of the union nut from its inner part, and the union nut is provided with additional internal threads for meeting with another hose.
However, there remains a need for a pipe or hose coupling having a coupling nut which is easily removable for interchanging other coupling nuts therefor, depending on a user's specific needs. Additionally, the coupling nut should not disengage from the end of the hose when coupling to another hose.